Light signal



W. B. WELLS Oct. 18, 1938.

LIGHT S IGNAL Filed June 10, 1936 2 Sheets-Sheet l INVENTOR Wsle . Wells HIS ATTORNEY W. B. WELLS Oct. 18, 1938.

LIGHT S IGNAL 2 Sheets-Sheet 2 Filed June 10, 1936 W 1 W??? es 0. e

' H15 ATTORNEY Patented Oct. 18, 1938 UNITED STATES PATENT OFFICE 2,133,603 LIGHT SIGNAL Application June 10,

3 Claims.

My invention relates to light signals, and particularly to light signals which are capable of selectively projecting a plurality of beams of light of different colors from a single light source.

More particularly, my present invention relates to operating mechanisms for such signals, and is an improvement on the operating mechanism described and claimed in Letters Patent of the United States No. 1,864,224, granted to me on June 21, 1932.

I will describe one form of mechanism embodying my invention, and will then point out the novel features thereof in claims.

In the accompanying drawings, Figs. 1 and 2 are rear elevational and right-hand end views, respectively, of the operating mechanism embodying my invention. Fig. 3 is an isometric view of the field structure forming part of the operating mechanism shown in Figs. 1 and 2. Fig. 4 is an isometric view of the rotor forming part of the operating mechanism shown in Figs. 1 and 2. Fig. 5 is a diagrammatic view showing a circuit for controlling the mechanism.

Similar reference characters refer to similar parts in each of the several views.

Referring to the drawings, the operating mechanism is of the three-position motor relay type, and in the form here shown comprises a field structure -A which is best illustrated in Fig. 3, and a rotor B which is best illustrated in Fig. 4. Referring to Fig. 3, the field structure A comprises two spaced magnets M and M the like poles of which are connected by spaced backstraps l0 and II, respectively. The magnets M and M may be of any suitable type, such for example, as the well-known electromagnets employing a magnetizable core carrying an energizing winding, but in order to decrease the cost of manufacture and to improve the efiiciency of the signal, I prefer to employ the construction illustrated in the drawings. As here shown, each magnet comprises two rectangular plates I and 2 of suitable magnetizable material, which plates are clamped between two pairs of vertically extending permanently magnetized rectangular bars 3 adjacent the upper and lower ends of the bars, respectively. The bars '3 of each pair are disposed in parallel spaced relation with one another, and are so arranged that their corresponding ends are all of the same polarity. These bars are removably maintained in position by means of a clamping bolt 4 which extends horizontally through retaining clips 5, and between the bars 3 of each pair of bars at a point approximately m dw y e een th ir nds; h ips 5, are

1936, Serial No. 84,501 (Cl. 1'77329) provided with ears 5 at each end, which ears overlap the opposite sides of the two bars of each pair for holding the bars in the proper spaced relation. To prevent the bolts 4 from turning while the associated nut 4 is being 5 tightened or loosened, an auxiliary clip 6 is interposed between the head of the bolt and the associated clip 5. This auxiliary clip extends transversely of the associated clip 5, and is provided at its inner side with a horizontal channel 6 which receives the associated clip 5, and on its outer side with spaced parallel ribs 6 which engage the opposite sides of the rectangular head of the bolt 4. A fiat locking plate 1 (see Fig. 2) is interposed between each nut 4 and the associated clip 5. This locking plate is made of deformable material, and after the nut is tightened, one end of this plate is bent into engagement with the edge of the associated clip, and the other end is bent into engagement with the nut, thus preventing the nut from becoming loosened. A spacing block 8 of brass or other suitable non-magnetizable material is interposed between the plates I and 2 of each magnet, and the spacing-block, plates, and backstraps are all securely fastened together by means which will be described hereinafter. Each block 8 is provided with a horizontal slot 9 through which the clamping bolt 4 passes with some clearance, and which is open at its outer end to permit the bolt to be inserted or removed from the slot by sliding it outwardly at right angles to the axis of the block 8. It will be noted that the width of the spacing block is less than the width of the plates l and 2, thus providing clearance between the block and the bars 3. Clearance is also provided between the ends of the bars and the backstraps I0 and I2. By means of this construction, the four bars of either magnet may be removed from the field structure for inspection or replacement merely by loosening the associated nut 4 and sliding the bolt, clips, and bars outwardly in the direction of the axes of the backstraps (see Figs. 1 and 2). Furthermore, with this construction, the remainder of the operating mechanism may be assembled before the bars are added to the field structure. This is ,a distinct advantage, because, if the magnetizable bars were assembled to the field structure before the remainder of the operating mechanism of the signal was'assembled, then while the remainder of the operating mechanism was being assembled, iron and steel filings might be attracted -to the bars, which is undesirable. By assembling the mechanism completely without .lli'and 11.

'H. l2 and 13 will be of one polarity, while the pole the bars, the operating mechanism can be cleaned either with a vacuum or a blast of air, and the bars can be freed of all filings and assembled as a last operation.

It should be pointed out that the magnetic contact between the bars 3 and the backstraps l0 and II is made through the medium of the plates l and 2, and not at the ends of the bars, so that no machining of the bars is necessary other than cutting them to the desired length, which operation need not be done with great accuracy. It will be seen, therefore, that magnets constructed in the manner shown are very economical to manufacture. It should also be pointed out that, while I have shown each mag-. net as comprising four permanently magnetized bars, this number is not essential to my invention, but may be varied in accordance with the field strength which it is desired to attain.

Associated with the backstrap ID are two pole pieces l2and I3, and associated with the backstrap II are two pole pieces l4 and I5. As here shown, these pole pieces are L-shaped, being formed with" horizontally extending legs l2, I3 Rand l5, respectively, and withvertically extending legs. l2, l3, l4, and I5 respectively. The horizontal leg of each pole piece .is fastened to the associated backstrap by means of screws Each screw 16. extends with clearance through .av suitable hole in the pole piece and is screwed into a threadedhole in the associated backstrap. Each screw II ---extends through a suitable clearance hole inthepole piece, into and 'througha threaded hole in the associated backstrap, and. througha clearance hole in theadjacent; plate: I or 2. It thenpasses into a' clearance hole in the adjacent-block 8. It thus prevents plateszl and-2 from turning about an associated tap bolt l9 described hereinafter. It will be apparent, therefore, that the screws I! serve both asa means" for fastening the pole pieces to the backstraps; and as-a. part of thermeans, referred to "hereinbefore. for fastening the "backstraps l I] and. I, plates l. and 2,.and spacing block 8 together. The 'pole..piecesl2 and I3 .are spaced apart, and are disposed with their vertical legs extending downwardly on opposite sides of the backstrap [0, and the pole pieces 14 and I5 are similarly-spacedapart andaredisposed with their vertical legs extending upwardly on opposite-sides of the backstrap ll directly .opposite the-down- .wardly extending legs of the pole pieces l2 and I3. =-For reasons which will appear hereinafter, the vertical legs I2 and l3 of the pole pieces l2 and l3 are made-sufficiently long so that they extend downwardly to apoint opposite the lower backstrap ll,-while the legs M and I5 of the pole pieces I4 and i5 are made relatively short. It-will be apparent, therefore, that the field structure embraces two pairs of'pole pieces, the one pair of which 12 and [S are located on one side of ,and adjacent; the opposite ends of, the back- .straps l0 and II, and the other pair of which l3 and: 14 are located on the other side of, and adjacent: the-opposite ends of, the backstraps I!) and It willaalso be apparent that the pole pieces pieces l4 and I5 will be of the opposite polarity. For example, if the bars 3 are disposed with their north magnetic poles located at the upper ends of screws 20 is a non-magnetizable bracket 2|. bracket is substantially U-shaped, and the upwardly extending arms 2| and 2| thereof are The tap bolts l9 referred to hereinbefore each pass through a clearance hole in the associated backstrap, into and through a clearance hole in the associated plates l and 2, and is screwed at its lower end into the spacing block 8. It will be noted that the tap bolts I!) serve as part of the means referred to previously for clamping the backstraps l0 and II, plates l and 2, andspacing blocks 8 together.

Attached to the lower backstrap I l by means of This provided in their upper ends with aligned knifeedge bearings22- and 23, respectively, in which the rotor B referred to hereinbefore is jo'urnaled,

as best seen in Fig. 2. The bearings 22 and 23 maybe of any'suitable construction but. as here shown, these bearings are similar in all respects 'to those described and claimed in my copending application :for Letters Patent'of the United States SerialTNo. 748,506, filed on October 16, 1934; for Bearings and: method of manufacturing thesame.

Referring now also to'Fig. 4, the rotor B, in the mounted to rotate in the knife-edge bearings previously described. The armature 26 is adapted to cooperate with the pole :pieces l2 and |5,'and is spaced. from the outer or pole faces of the vertical legs I2 and [5 of these pole pieces by vertical air gaps; aswill be seen from an inspection of Fig. 2.

The-armature 21 is likewise adapted to cooperate with the polepieces l3=and l4, and is spaced from the outer or pole faces of the vertical legs l3 and l 4 of these pole pieces by vertical air gaps. The armatures 26-and-21 are-of magnetizable material, and are providedwith ears 26, 26*,21, and

21 which taper from the center of the armature as shown, the F reasons for tapering these ears being explained hereinafter.

- Clamped between the nut- 28 and the armature 26is-a triangular bracket-34, and attached to the ,outerside of this'bracket on opposite sides of the core"25' of-the rotor B, as best seen in-Figs.

-1 and 2, are two studs 30 and 3| which carry rollers 30%an'cl" 3|, respectively. "Ihese rollers cooperatewith-suitable-means (not shown) for biasing the rotor to a middle or normal position in which the longer axes of the armatures 26 and 2! are substantially vertical, and also with suitable-contact mechanism (not shown) which is selectively"operatedin response to rotation of the armature. These biasing means and contact mechanism form no part of my present invention and may, for example, be similar to that described in myprior United States Patent No. 1,864,224 referred to hereinbefore. It will be obvious that the'qarmatures 26 and 21. due to the manner in =whichthey are disposed also serve to bias the rotor to its normal position.

A spectacle arm '32 isrigidly attached at its lower end to the armature 21 of the rotor B in such manner that, when the rotor occupies its normal position, the spectacle arm will be vertical, and this spectacle arm is providedat its upper end with three filters G, R, and Y which cooperate with the optical system of the signal in which the operating mechanism is used in a manner which is fully described in my above referred to patent, to cause the signal to indicate proceed, stop, or caution according as the rotor is swung to a left-hand extreme position, occupies its intermediate position, or is swung to a righthand extreme position, as viewed in Fig. 1. The parts are so proportioned that the spectacle arm is substantially counterbalanced by the armatures 26 and 21, whereby a balanced rotor is obtained without the necessity of additional counterbalancing means.

A slow-acting coil 35 surrounds the core 25 of the rotor R, and is held in place by two brackets 36 which are secured intermediate their ends to the backstraps I and II, respectively, and which fit into suitable slots formed in the insulating end plates of the coil. The construction of the coil 35 and the method of securing it to the backstraps form no part of my present invention, and may, for example, be similar to that shown in my prior Patent No. 1,864,224. The coil 35 is intended to be reversibly supplied with current, and for this purpose I have shown in Fig. 5, a battery C which is connected with this coil over a pole changer P. As illustrated in the drawings, the pole changer is manually operated, but in actual practice this pole changer will normally be replaced by pole-changing contacts of a relay, or by contacts operated by another mechanism similar to that shown herein.

Assuming for purposes of explanation that the magnets M and M are so disposed that the pole pieces I2 and I3 become north poles, and the pole pieces I4 and I5 become south poles, the operation of the operating mechanism as a Whole is as follows: When pole changer P occupies its middle position in which no current is supplied to the coil 35, as shown in the drawings, the only flux which threads the armatures 26 and 21 is the flux from the associated pole pieces I2, I5, I3, and I4, and the armatures are so shaped and the parts are so proportioned that this flux will exert no appreciable torque on the rotor. Under these conditions, the rotor is held, due to the biasing means referred to hereinbefore, in its intermediate position in which the signal displays a stop indication.

If, now, pole changer P is thrown in such a direction that winding 35 is supplied with current of normal polarity, armature 26 becomes a north pole and armature 21 becomes a south pole. Under these conditions, the pole piece I2, being a north pole, repels -the armature 26, and the pole piece I5, being a south pole, attracts the armature 26, while the pole piece I3, being a north pole, attracts the armature 21, and the pole piece I4, being a south pole, repels the armature 21. A torque is therefore exerted on rotor R which torque rotates the rotor in a counterclockwise direction, as viewed in Fig. 1, to its left-hand extreme position in which it is stopped by means of the mechanism which is actuated by the roller 3%. When the rotor occupies its lefthand extreme position, the signal displays a proceed indication as explained hereinbefore.

If pole changer P is thrown in such a direction that coil 35 is supplied with current of reverse polarity, armature 26 then becomes a south pole and armature 21 becomes a north pole. Under these conditions, armature 26 is attracted by pole piece I2 and repelled by pole piece l5, while armature 21 is repelled by pole piece I3 and attracted by pole piece I4, so that a torque is exerted on rotor R which rotates it in a clockwise direction, as viewed in Fig. 1, to its righthand extreme position in which it is stopped by means of the mechanism which is actuated by the roller 30 When the rotor occupies its righthand extreme position, the signal displays a caution indication, as explained hereinbefore.

It should be particularly pointed out that with the armatures 26 and 21 mounted in depending vertical positions in the manner described, the rotor may be made considerably lighter in weight than has heretofore been possible. This reduction in weight of the rotor is desirable for two reasons. In the first place, it reduces the weight on the knife-edge bearings, thus increasing their life. In the second place, it reduces the momentum attained by the rotor when travelling from one extreme position to the other, and hence decreases the tendency of the rotor to rebound when it reaches either extreme position.

It should also be particularly pointed out that with the armatures 26 and 21 mounted in depending vertical positions inthe manner described, the magnetic pull which is exerted on these armatures when the coil 35 is energized is a downward pull toward one side or the other, depending upon the direction of energization of the coil, thus insuring that the rotor Will not be lifted off of its bearings.

only one form of signal mechanism embodyingmy invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. An electroresponsive device comprising a field structure consisting of two magnets having their like poles connected by vertically spaced horizontally extending backstraps, first and second pole pieces secured to the upper backstrap adjacent the opposite ends thereof and third and fourth pole pieces secured to the lower backstrap below said first and second pole pieces, respectively, said first pole piece being provided with a depending vertical portion which is disposed on the same side of said field structure, and in the same vertical plane, as an upwardly extending vertical portion which is provided on said fourth pole piece, and said second pole piece being provided with a depending vertical portion which is disposed on the opposite side of said field structure from the depending portion of said first pole piece and in the same vertical plane as an upwardly extending vertical portion which is provided on said third pole piece, a rotor comprising two depending armatures connected by a magnetizable core and one separated from the vertical portion of said first and fourth pole pieces by vertical air gaps and the other separated from the vertical portions of said second and third pole pieces by vertical air gaps, and means for reversibly supplying fiux to said rotor.

2. An electroresponsive device comprising two magnets each consisting of a plurality of permanently magnetized bars clamped against two magnetizable plates located adjacent the upper and. lower ends of-the bars respectively, said bars being disposed in. such manner that their corresponding ends areall of the same polarity, two backstraps one fastened to the corresponding plates ofboth magnets at each end of the magnets for connecting the like poles of the magnets together, two. pairs ofv pole pieces attached to said backstraps in such manner that the polepieces of each pair are-of opposite polarity and are laterally spaced from each other and are provided with pole faces which are located in the same vertical plane, the corresponding pole pieces of the'two pairs of pole pieces being of the same polarity, a rotor comprising two depending armatures connected by a'magnetizable core and one separated adjacent'its lower end from the pole pieces of each pair by vertical air gaps, and a fixed coil. surrounding said core for reversibly supplying flux to said rotor.

3. A light'signal comprising'an electroresponsive device including'arotor having two depending armatures connected by a magnetizable core, said. rotor being. rotatable between two extreme positions, an upwardly extending spectacle arm secured to the rotor, said spectacle arm and said armatures being so proportioned that said spectacle arm is substantially; counterbalanced by said armatures; means for reversibly supplying flux to said rotor, a'first :pair of constantly magnetized pole pieces of opposite polarity disposed on opposite-sides of the vertical plane passing through the axis of said rotor and having-pole faces disposed in thesamevertical plane and separated from the one armature adjacent its lower end by verticallair gaps in-such manner that the one polepiece ofv said first pair will attract and the other 'willrepel said armature or vice versa according as said rotor is supplied with flux of one polarity or the other, and asecond pair of constantly magnetized polepieces of opposite polarity disposed on opposite sides of the vertical plane passing through the axis of said rotor and having-pole faces disposed in the same vertical plane and separated irom the other armature adjacent its lower end byvertical air gaps in such manner that the one pole piece of said second pair willattractand the other pole piece will repelsaid :otherarmature or vice versa according as said'rotor is-supplied with flux of one polarity :orthe other,-said two pairs of pole pieces being so arranged that the torques exerted on the rotor by both armatures at any instant will be additive.

WESLEY B. WELLS. 

